Slush mold methods and apparatus have been used for processing plastic powder to form articles such as interior door panels having two or more tone colors.
Generally, the mold apparatus includes a mold body having a molding surface which is clamped to a plastisol charge box. The plastisol charge box includes at least one divider for dividing the box into plural sections, each section containing a different color plastisol. As disclosed in the Gray U.S. Pat. No. 4,562,025, issued Dec. 31, 1985, Gray U.S. Pat. No. 4,610,620, issued Sept. 9, 1986, and Kurimoto U.S. Pat. No. 4,783,302, issued Nov. 8, 1988, the divider extends from the powder box so as to sealingly engage the mold surface of the mold box. The mold box is clamped to the powder box. The mold surface is heated, such as by convection current, hot oil, or other means known in the art. The charge box and mold are then rotated so that the plastisol is distributed into each mold section by gravity flow with the plastisol from each section flowing to the divider which separates this color so as to form two or more tones on a resultant shell of cured material.
Presently, two tone color changes are made by first emptying the dry plastisol or drysol out of the powder box and then vacuuming the remaining loose powder out of the box before adding the desired new color. A similar procedure is used with monotone and two tone casting processes.
In using the prior art system, before an elevator containing the powder box can be retracted from the mold box, the elevator must be lowered the total distance from the top of the powder box divider to the top of the two tone seal, dictating facility capability.
The present invention provides a more efficient and effective means allowing color change without the previously necessary emptying and vacuuming of a powder box associated with a single mold assembly. The present invention allows on-line color changes without emptying and cleaning of the complete powder box. The present invention further reduces the set up time of a two tone seal and divider panel system.